The invention discloses a method for preparing a Ni/MgO-Al2O3 catalyst for coproduction of methylisobutylketone and diisobutylketone, and relates to a chemical solvent. In the method, a Ni/MgO-Al2O3 catalyst is used, the catalyst consists of 4 weight percent of Ni, 53 weight percent of MgO and 43 weight percent of Al2O3, and the catalyst is prepared from a reconfigured NiMgAl hydrotalcite-like compound at the reaction temperature of between 150 and 240 DEG C at the liquid space velocity of 2.4 to 4.8 ml/gcat.h in a molar ratio of hydrogen to ketone of 0.5-2; and in a fixed bed reactor, the conversion rate of acetone is 30 to 56 percent, and the selectivity of the methylisobutylketone reaches 57 to 69 percent. Ni<2+> of the Ni/MgO-Al2O3 catalyst prepared by a reconfigured hydrotalcite-like method is mainly distributed on the surface of the catalyst, is easy to reduce, is used in the reaction of synthesizing MIBK by an acetone gas phase one-step method, and has high catalytic performance.